1. Field of the Invention
The present invention relates to a process of press-forming deep-drawn products having different lengths and an apparatus for carrying out the process.
2. Description of the Related Art
A known press-forming process uses a die composed by combining unit block tools to produce deep-drawn products with arbitrary shapes. Specifically, a plurality of unit block tools having selected shapes are combined to form a punch, a die and a blank holder so that deep-drawn products having different shapes can be produced. This enables press-forming die assemblies having different shapes to be provided by combining a plurality of unit block tools, and thus, deep-drawn products having different lengths can be press-formed without an increase in the number of press-forming die assemblies.
The conventional art, however, has a problem that a die assembly of combined unit block tools cannot simultaneously effect press-forming and trimming, and therefore, the die assembly must be changed to produce a deep-drawn product having a different length when the press-forming process includes trimming as well as forming. Particularly, to produce deep-drawn products with different lengths varying at small pitches, a great number of die assemblies must be prepared accordingly, which requires a heavy die cost and much time for changing die assemblies, lowering the rate of operation, and thereby increasing the gross production cost.